JP10-81310A describes a system in which a band-shaped film is formed into a tube-shape which surrounds the circumference of respective blocks of meat which move along a linear travel path, at equidistant intervals. The tube film into which a respective block of meat has been packaged is cut successively and separated, and each individual packaging bag containing a block of meat is supplied successively to a pressure resistant chamber of a rotary vacuum packaging device, by means of a belt conveyor. By means of this system, since a control is provided which causes the interval between the respective blocks of meat having an indefinite shape contained inside the bags to correspond to the pitch of the pressure resistant chambers which rotate at equidistant intervals, each block of meat can be disposed along the sealing platform of a pressure resistant chamber, whereas since differences in length occur respectively in the blocks of meat of indefinite shapes, a space may occur within each bag.
Furthermore, JP57-37525A discloses vacuum packaging technology, in which the end of a long tubular film which has already been formed to a shape is opened up, and an item to be packaged is pushed inside the tubular film via the open section. An operation is repeated wherein after the item to be packaged has been pushed inside the tubular film, the tubular film is cut, and the cut packaged bodies are then inserted successively into a pressure resistant chamber, and either end of the packaged body is heat sealed by means of a sealing bar under vacuum conditions. However, with a vacuum packaging device of this kind, too, excessive space occurs inside the bags when packaged objects are of indefinite shapes.
In contrast to the commonly known examples described above, JP49-72082A, JP58-203827A, and the like disclose technology in which the uppermost bag of stacked bags is opened up by air pressure, an item to be packaged is introduced into the bag via the opening thereof, and is then conveyed together with the bag. By using this technology, it is thought to be possible to convey blocks of meat inside bags in a fitted manner along the sealing platform of a vacuum chamber. However, a distortion or slack is caused to occur at the mouth of the bag during transportation, which impairs the vacuum sealing properties of the packaged body. If such distortion or slack of the bag is removed while the bag is on the sealing platform, the efficiency of the rotary vacuum packaging device is adversely affected.